Airbag assembly

ABSTRACT

An airbag assembly comprises an airbag cushion, an inflator to provide inflation gas to inflate the airbag cushion, and a diffuser provided between the inflator and the airbag cushion. The diffuser includes a plurality of panels. The plurality of panels force the inflation gas to change flow direction at least two times before the inflation gas exits into the airbag. The panels each include openings for inflation gas to pass through. Openings in a first panel are not aligned with the openings in a second panel.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/213,037, filed Apr. 30, 2009, which is incorporated herein byreference in its entirety.

BACKGROUND

The present application relates generally to the field of vehicleairbags. More specifically, the application relates to a diffuser for anairbag module with a complex path for escaping gasses.

An inflatable airbag that uses an inflation device that generates gasthrough pyrotechnic ignition, stored gas or combination thereoftypically requires diffusion of the gas into the airbag cushion toproperly inflate the cushion and preserve the integrity of the cushionfabric. The need for a diffuser is especially apparent in high pressuresystems, fast deploying systems, or systems where gas generation createslarge amounts of heat and/or particulate from the combustion process.Such diffusers generally include a deflection surface or plate that isperpendicular to the path of the gas from the gas generator. The gas isthen redirected through outlet passages to the interior of the airbagcushion to inflate the airbag cushion.

Current air bag diffusers employ an open path diffusion method whereinflation gasses have direct line of sight with the outlet passages ofthe gas diffuser. This line of sight can be from several directions,side to side (e.g., a loop diffuser, as shown in FIG. 8), directional inonly one direction (e.g., to the bottom, as shown in FIG. 9), ormulti-directional (e.g., a gas sleeve, as shown in FIG. 10). However,with each of the existing types of diffusers, the inflation gas onlychanges directions one time before exiting the diffuser.

It would be desirable to provide a diffuser that redirects the inflatinggasses multiple times to better diffuse the inflating gas and trap anyparticulate byproducts from the gas generation process.

SUMMARY

One embodiment of the invention relates to an airbag assembly. Theairbag assembly includes an airbag cushion, an inflator to provideinflation gas to inflate the airbag cushion, and a diffuser providedbetween the inflator and the airbag cushion. The diffuser includes aplurality of panels. The plurality of panels force the inflation gas tochange flow direction at least two times before the inflation gas exitsthe diffuser and enters into the airbag.

Another embodiment relates to an airbag assembly. The airbag assemblyincludes an airbag cushion, an inflator to provide inflation gas toinflate the airbag cushion, and a diffuser provided between the inflatorand the airbag cushion. The diffuser includes a first panel and a secondpanel. The first and second panels each include openings for inflationgas to pass through. The openings in the first panel are not alignedwith the openings in the second panel.

Still another embodiment relates to a method of making a diffuser for anairbag assembly. The method includes providing first and second panels,providing openings in each of the first and second panels, overlayingthe second panel on the first panel, folding the overlayed panels alongcentral longitudinal midline of the overlayed panels, and attaching thefolded and overlayed panels to an inflator and/or airbag cushion.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory only,and are not restrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate preferred embodiments of theinvention and together with the description serve to explain principlesof the invention.

FIG. 1A is a perspective view of a portion of a vehicle interiorincluding an airbag assembly with a diffuser according to an exemplaryembodiment.

FIG. 1B is a perspective view of a vehicle including an airbag assemblywith a diffuser according to an exemplary embodiment.

FIG. 2 is a cross-section of a prior art airbag assembly.

FIG. 3 is a front view of a first panel for a diffuser with complexpaths between the inlet and the outlets according to an exemplaryembodiment.

FIG. 4 is a front view of a second panel for a diffuser with complexpaths between the inlet and the outlets according to an exemplaryembodiment.

FIG. 5 is a front view of the panels of FIGS. 3 and 4 overlayedaccording to an exemplary embodiment.

FIG. 6 is front view of a diffuser with complex paths between the inletand the outlets according to an exemplary embodiment, in which theoverlayed panels of FIG. 5 have been folded along a midline.

FIG. 7 is a cross-section view of the diffuser of FIG. 6 taken alongline 7-7 showing the complex paths of the inflation gasses between theinlet and the outlet, when the diffuser is arranged in an airbagassembly with an airbag cushion and inflator.

FIG. 8 is a front view of a prior art diffuser with outlets on eitherside.

FIG. 9 is a front view of a prior art diffuser with unidirectionaloutlets along the bottom.

FIG. 10 is a front view of a prior art diffuser with multidirectionaloutlets on the top and bottom.

DETAILED DESCRIPTION

Referring to FIGS. 1A and 1B, a vehicle 10 is shown according to anexemplary embodiment. The vehicle 10 includes one or more seats that areconfigured to receive an occupant and are coupled to the vehicle.Airbags and airbag modules 20 may be provided at a variety of placeswithin the vehicle to protect an occupant of the vehicle in a variety ofimpact scenarios. For example, airbags may be provided in the dashboard,proximate to the steering wheel, in the vehicle seats, in the door trimpanels, in the headliner, etc. According to one exemplary embodiment,shown in FIG. 1A, a steering wheel airbag assembly 20 is coupled to thesteering column. According to another exemplary embodiment, as shown inFIG. 1B, a side airbag assembly 20 is coupled to the vehicle seat.

The conventional prior art airbag assembly 120 of FIG. 2 includes aninflator (e.g., gas generator) 124, a diffuser 130, and an airbagcushion 122. The inflator 124, such as a pyrotechnic gas generator,generates a gas that rapidly inflates the airbag cushion 122 in animpact or vehicle collision. The diffuser 130 is provided between theinflator 124 and the airbag cushion 122. An airbag assembly 120 thatuses an inflation device (e.g., inflator 124) that generates gas throughpyrotechnic ignition, stored gas or combination thereof typicallyrequires diffusion of the gas into the airbag cushion 122 to properlyinflate the cushion and preserve the integrity of the cushion fabric.The need for a diffuser 130 is especially apparent in high pressuresystems, fast deploying systems, or systems where gas generation createslarge amounts of heat and/or particulate from the combustion process.Such diffusers 130 generally include a deflection surface or plate 136that is perpendicular to the path of the gas from the gas generator 124.The gas is then redirected through outlet passages 138 to the interiorof the airbag cushion 122 to inflate the airbag cushion 122. Thediffuser 130 is configured to diffuse the inflating gas and trap anyparticulate byproduct generated by the gas generator 124. However, sucha conventional diffuser 130 allows the inflating gas to have a commondirection and a direct line of sight from the inflator 124 to theoutlets 138.

Referring to FIGS. 3-7, an airbag assembly 20 is shown. The airbagassembly 20 may be similar to the assembly 120, but includes an improveddiffuser 30 that creates a complex path between the outlets of theinflator 24 and forces the inflating gas to change directions multipletimes (such as shown by the arrows in FIG. 7). The diffuser 30 isprovided in the interior volume of the airbag cushion 22 and directscombustion gasses produced by the inflator 24 into the airbag cushion 22to inflate the airbag cushion 22. The multiple changes of direction helpto better trap any particulates that may be formed during the combustionprocess. The diffuser 30 is configured, in embodiments, to diffuse theinflation gas and take the directional flow of the gas and alter theflow into a non-specific direction. The diffuser 30 can effectivelycreate a semi-laminar non-directional flow of gas.

According to one exemplary embodiment, as an inflating gas enters theairbag cushion 22, the airbag cushion 22 bursts through an outer skin orcover of the airbag assembly 20 and inflates between the occupant of thevehicle and the steering wheel, dashboard, or other structural member ofthe vehicle. For instance, the airbag cushion 22 may emerge from belowthe outer covering of the steering wheel, through a cutaway in a trimpanel, from behind a trim panel, from a seam between two panels orcoverings, etc. According to various embodiments, the airbag assembly 20may be configured within a glove box assembly or in other locationswithin the vehicle, such as beneath trim panels along the roof rail,trim panels along the vertical pillars (e.g., the A-pillar, B-pillar,and C-pillar), with the seat assembly, etc. The airbag assembly 20 isflexibly configurable for use in varying package requirements, and maybe tailored to satisfy specific needs of the vehicle manufacturer.

According to an exemplary embodiment, the diffuser 30 may be formed byconnecting a pair of fabric panels 32 and 34. The first fabric panel 32(FIG. 3) and the second fabric panel 34 (FIG. 4) are flexible membersthat may be formed from a traditional airbag material, such as highstrength nylon. Because they are formed from a flexible fabric material,the panels 32 and 34 can be folded into a compact package with theairbag cushion 22 when the airbag assembly 20 is stowed behind a trim orcover component.

The first panel 32 and the second panel 34 each include a neck portion36 that forms an inlet and a plurality of openings 38, shown asgenerally circular holes. The first panel 32 and the second panel 34 areoverlayed as shown in FIG. 5. The openings 38 in the first panel 32 andthe second panel 34 are configured such that the openings 38 in thefirst panel 32 do not align with the openings 38 in the second panel 34when the panels 32 and 34 are overlayed. According to one exemplaryembodiment, the hole pattern in the first panel 32 is a mirror image ofthe hole pattern in the second panel 34. While the panels 32 and 34 areeach shown having four identical openings 38 arranged as mirror imagesrelative to each other, it should be understood that many variations arepossible. For example, the openings 38 may not be round but may insteadbe rectangular, oblong, or otherwise shaped. The openings 38 on thefirst panel 32 or on the second panel 34 may not be a uniform size. Eachof the panels 32 and 34 may include openings 38 of several differentshapes and sizes. The openings 38 in the second panel 34 may differ insize, shape, number, or arrangement compared to the openings 38 in thefirst panel 32.

To construct the diffuser 30, the overlayed panels 32 and 34 are foldedin half along their respective midlines 35 and the edges 37 sewntogether. Two edges 37 of the first panel 32 and two edges of the secondpanel 34 are couple together along the sewn seam. Once folded in halfand sewn together, the first panel 32 forms an inner chamber 40 that isnested inside an outer chamber 42 formed by the second panel 34, asshown best in FIG. 7. The neck portions 36 of the panels 32 and 34 forman inlet that allows inflating gas from the gas generator 24 to enterthe inner chamber 40 formed by the first panel 32. A mounting tab 39facilitates coupling the diffuser 30 to the gas generator 24 and thevehicle frame (e.g., with a retainer or other mounting device). Whilethe panels 32 and 34 are described as being sewn together, in otherembodiments, the edges 37 may be otherwise coupled together, such aswith an adhesive, heat sensitive material, etc.

In other embodiments, the diffuser 30 may be made from more than twopanels. One or more panels may be used to form an inner chamber 40 andone or more panels may be used to form an outer chamber 42. For example,according to another exemplary embodiment, the first panel 32 and thesecond panel 34 shown in FIGS. 3 and 4 may replaced by two panels each.The four panels may be overlayed and the edges coupled together to forman inner chamber 40 and an outer chamber 42 similar to that seen in FIG.7, but coupled together on two sides, when seen in cross section,instead of one side. In an embodiment, any suitable number of panels maybe used to form the diffuser 30. For example, the diffuser 30 can havethree, four, five, six or more panels. The panels may have the samemirror image and offset hole pattern configuration as described above.The more panels that a diffuser 30 comprises will create more layers forgas diffusion and particulate entrapment.

The gas from the gas generator 24 enters the inner chamber 40 formed bythe first panel 32 through the neck portion 36. The gas then passesthrough the openings 38 in the first panel 32 into the outer chamber 42between the second panel 34 and the first panel 32. Once in the outerchamber 40, the gas is forced to change direction by the fabric of thesecond panel 34 and flows sideways between the first panel 32 and thesecond panel 34. Once the inflation gas reaches the openings 38 in thesecond panel 34, the gas changes direction again and escapes into theairbag cushion 22 to inflate the airbag cushion 22. The gas is shown tofollow symmetrical paths on the top of the diffuser 30 and the bottom ofthe diffuser 30. In other embodiments, depending on the size, shape,arrangement, and number of openings 38 in the first panel 32 and thesecond panel 34, a greater percentage of the total flow of gas may passthrough openings 38 on the top of the diffuser 30 or the bottom of thediffuser 30. In other embodiments, openings 38 may only be provided oneither the top of the diffuser 30 or the bottom of the diffuser 30. Instill other embodiments, gas may be directed out of the inner chamber 40through openings 38 on one side of the diffuser 30 and be directed on alonger path through the outer chamber 42 to exit the diffuser 30 throughopenings 38 on the opposite side of the diffuser 30.

By forcing the inflation gas to follow a complex and indirect path intothe airbag cushion 22, the diffuser 30 is able to more effectively trapparticulates compared to conventional diffusers in which the inflationgasses have a direct line of sight from the inflator to the outletpassages of the gas diffuser, as shown in FIGS. 8-10. More effectivelytrapping the particulates reduces the likelihood that the particulateswill escape into the airbag cushion and cause any undesirable damage tothe cushion.

Further, the diffuser 30 as shown in FIGS. 3-7 reduces the amount ofheat to which the airbag cushion 22 is exposed. As the hot inflationgasses pass from the gas generator 24 through the complex path passingthrough the inner chamber 40 and the outer chamber 42, the diffuser 30is able to absorb more heat from the gasses.

Forming the diffuser 30 from fabric panels 32 and 34 reduces the costand overall airbag envelope size compared to gas diffuser formed fromplastic or metal. Further, the flexible nature of the panels 32 and 34allows the diffuser 30 to be folded, rolled, or otherwise compacted withthe airbag cushion 22. In this way, the overall size of the stowedairbag assembly 20 can be reduced and the shape of the stowed airbagassembly 20 may be adapted to fit a wide variety of mounting locations.

While the diffuser 30 is shown in the figures as being configured foruse with a driver's airbag assembly mounted to the steering column (FIG.1A) or a seat-mounted side airbag (FIG. 1B), the novel ideas embodied inthe diffuser 30 may be adapted to a wide range of other airbagassemblies. For instance, the diffuser 30 with a complex path may beused for a passenger side airbag and be mounted to the vehicle dash.According to other exemplary embodiments, the diffuser 30 with a complexgas path may be used for knee airbag assemblies, or side or rear curtainairbag assemblies.

It is to be understood that both the foregoing general description anddetailed description are exemplary and explanatory only, and are notrestrictive of the invention.

For purposes of this disclosure, the term “coupled” means the joining oftwo components (electrical or mechanical) directly or indirectly to oneanother. Such joining may be stationary in nature or movable in nature.Such joining may be achieved with the two components (electrical ormechanical) and any additional intermediate members being integrallyformed as a single unitary body with one another or with the twocomponents or the two components and any additional member beingattached to one another. Such joining may be permanent in nature oralternatively may be removable or releasable in nature.

The construction and arrangement of the diffuser as shown in thepreferred and other exemplary embodiments is illustrative only. Althoughonly a few embodiments of the present airbag assembly have beendescribed in detail in this disclosure, those skilled in the art whoreview this disclosure will readily appreciate that many modificationsare possible (e.g. variations in sizes, dimensions, structures, shapesand proportions of the various elements, values of parameters, mountingarrangements, use of materials, orientations, etc.) without materiallydeparting from the novel teachings and advantages of the subject matterrecited in this disclosure. Accordingly, all such modificationsattainable by one versed in the art from the present disclosure withinthe scope and spirit of the present invention are to be included asfurther embodiments of the present invention. The order or sequence ofany process or method steps may be varied or re-sequenced according toalternative embodiments. Other substitutions, modifications, changes andomissions may be made in the design, operating conditions andarrangement of the preferred and other exemplary embodiments withoutdeparting from the spirit of the present application.

1. An airbag assembly, comprising: an airbag cushion; an inflator toprovide inflation gas to inflate the airbag cushion; and a diffuserprovided between the inflator and the airbag cushion, the diffuserincluding first and second overlaying panels, wherein the first panelhas at least one opening overlaying a wall portion of the second panelsuch that the inflation gas flowing through the at least one opening isforced to change flow direction at least two times before the inflationgas exits the diffuser and enters into the airbag cushion.
 2. The airbagassembly of claim 1, wherein the first and second panels trapparticulates from the inflation gas to prevent particulates fromentering into the airbag cushion.
 3. The airbag assembly of claim 1,wherein the first and second panels are fabric panels.
 4. The airbagassembly of claim 1, wherein the first and second panels have a sameoverall shape when unfolded.
 5. The airbag assembly of claim 4, whereinthe second panel includes at least one opening for the inflation gas topass through, and wherein the second panel overlays the first panel sothat the at least one opening in the second panel is not aligned withthe at least one opening in the first panel.
 6. The airbag assembly ofclaim 4, wherein the first panel comprises a plurality of openings,wherein the second panel includes a plurality openings for the inflationgas to pass through, and wherein a pattern of the openings in the firstpanel is a mirror image of a pattern of the openings in the secondpanel.
 7. The airbag assembly of claim 1, wherein each of the first andsecond panels includes a body portion with a neck portion, the neckportion forming an inlet for the inflation gas to enter the diffuser,and wherein the second panel includes at least one opening in the bodyportion.
 8. The airbag assembly of claim 7, wherein the diffuser isconfigured so that the inflation gas enters an inner chamber of thediffuser via the neck portion of the first panel, then the inflation gaspasses through the at least one opening in the first panel to enter intoan outer chamber of the diffuser, wherein the inflation gas then passesthrough the at least one opening in the second panel to enter into theairbag cushion.
 9. An airbag assembly, comprising: an airbag cushion; aninflator to provide inflation gas to inflate the airbag cushion; and adiffuser provided between the inflator and the airbag cushion, thediffuser including a first panel and a second panel, wherein the firstand second panels each include a plurality of openings for the inflationgas to pass through, and wherein the plurality of openings in the firstpanel are not aligned with the plurality of openings in the secondpanel.
 10. The airbag assembly of claim 9, wherein the first and secondpanels trap particulates from the inflation gas to prevent particulatesfrom entering into the airbag cushion.
 11. The airbag assembly of claim9, wherein the first and second panels are fabric panels.
 12. The airbagassembly of claim 9, wherein a pattern of the openings on the secondpanel is a mirror image of a pattern of the openings in the first panel.13. The airbag assembly of claim 9, wherein each of the first and secondpanels includes a body portion with the openings and a neck portion, theneck portion forming an inlet for the inflation gas to enter thediffuser.
 14. The airbag assembly of claim 13, wherein the diffuser isconfigured so that the inflation gas enters an inner chamber of thediffuser via the neck portion of the first panel, then the inflation gaspasses through the openings in the first panel to enter into an outerchamber of the diffuser, wherein the inflation gas then passes throughthe openings in the second panel to enter into the airbag cushion.
 15. Amethod of making a diffuser for an airbag assembly, comprising:providing first and second panels; providing openings in each of thefirst and second panels; overlaying the second panel on the first panel;folding the overlayed panels along a central longitudinal midline of theoverlayed panels; and attaching the folded and overlayed panels to aninflator and/or airbag cushion.
 16. The method of claim 15, wherein whenthe panels are overlayed, the openings in the first panel do not alignwith the openings in the second panel.
 17. The method of claim 15,further comprising sewing together edges of the folded and overlayedpanels.
 18. The method of claim 15, wherein the first panel forms aninner chamber for the diffuser, and the second panel forms an outerchamber for the diffuser.